三种有机酸对磷酸钙法回收模拟养猪场污水中磷的影响

采用磷酸钙(Calcium Phosphate,CP)结晶法回收模拟养猪场污水中的磷,考察了不同pH值条件下,3种有机酸(柠檬酸、丁二酸和乙酸)对模拟污水中磷去除率的影响,并利用扫描电镜和X射线衍射仪对结晶产物进行了表征.结果表明,CP结晶反应的最佳pH值约为9.5.在相同pH值条件下,柠檬酸对CP结晶反应中磷的去除效率和速率均有显著影响,高浓度柠檬酸能够完全抑制CP结晶反应,导致磷的去除率小于5%.相比之下,丁二酸和乙酸对磷的去除效率和速率影响不明显.3种有机酸对CP结晶产物的形状没有明显影响,所得产物均呈不定形的块状,但产物体积大小会随有机酸浓度升高而明显减小.不同浓度丁二酸和乙酸存在条件下均能得到羟基磷酸钙(Hydroxylapatite,HAP)晶体,但柠檬酸的存在会影响所得产物晶形.     

流化床工艺在水处理中的应用研究进展

流化床工艺是一种工程应用前景广阔的处理技术,近年来该技术备受水处理研究者的青睐。已经研究出了多种反应器结构和工艺组合,如鸟粪石结晶流化反应器、三相生物流化床,具有结构紧凑、反应速度快,易于操作的优点。根据废水中污染物的去除机理将流化床归为流化床结晶反应器和流化床生物反应器两大类,论述该工艺在含磷、含氟、含硫废水,印染废水,农药废水及其他工业废水中的应用研究现状,展望了流化床反应器的发展趋势。     

Synthesis and characterisation of potassium polytitanate for photocatalytic degradation of crystal violet

Potassium titanate nanostructures were synthesised by hydrothermal treatment of TiO2 （P25） in KOH and H2O2. As-produced powders were characterised by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption methods. Longitudinally-oriented-wire-like structures with a length up to several micrometres and diameters ranging from 10 to 30 nm were obtained. Larger size fibrous nanowires resulting from the hydrotherrnal treatment showed high affinity in adsorbing crystal violet （CV）, which was mainly due to their high surface area. The photocatalytic bleaching of CV solution revealed that the wires are photoactive under ultraviolet light irradiation. Macroporous nanowires are considered as effective adsorbents of CV, capable of photocatalvtic degradation, and they can be easily separated from the solution by settling.     

Phosphorus recovery from wastewater by struvite crystallization：Property of aggregates

Struvite crystallization is a promising method to remove and recover phosphorus from wastewater to ease both the scarcity of phosphorus rock resources and water eutrophication worldwide. To date, although various kinds of reactor systems have been developed, supporting methods are required to control the struvite fines flushing out of the reactors. As an intrinsic property, aggregation is normally disregarded in the struvite crystallization process, although it is the key factor in final particle size and therefore guarantees phosphorus recovery efficiency. The present study developed a method to analyze the characteristics of struvite aggregates using fractal geometry, and the influence of operational parameters on struvite aggregation was evaluated. Due to its typical orthorhombic molecular structure, struvite particles are prone to crystallize into needle or rod shapes, and aggregate at the corners or edges of crystals. The determined fractal dimension(Dpf) of struvite aggregates was 1.52–1.31, with the corresponding range of equivalent diameter(d0.5) at 295.9–85.4 μm. Aggregates formed in relatively low phosphorus concentrations(3.0–5.0 mmol/L) and mildly alkaline conditions(pH 9.0–9.5) displayed relatively compact structures, large aggregate sizes and high aggregation strength. Increasing pH values led to continuous decrease of aggregate sizes, while the variation of Dpfwas insignificant. As to the aggregate evolution, fast growth in a short time followed by a long steady stage was observed.     

X射线衍射和红外光谱法分析高岭石结晶度

用X射线衍射和红外光谱法研究了浙江临安纤岭一带高岭石样品(A,B,C,D四个样品)的结晶度,并考察两种方法分析结果的相关性。分析结果表明B样品的Hinckley指数为1.28、红外结晶指数为1.57,结晶度最好。两种方法相关性较好,均可用来分析高岭石结晶度。     

醌基功能型高分子生物载体(PET-AQS)制备及催化生物反硝化特性研究

通过化学合成,将蒽醌磺酸钠(AQS)固定在聚对苯二甲酸乙二醇酯(PET)上形成醌基功能型高分子生物载体并研究其在生物反硝化上的应用.通过红外光谱衰减全反射法(ATR-IR)和能谱(EDS)分析,醌基基团成功固定在高分子表面,且醌基质量摩尔浓度为0.140 6 mmol·g-1.醌基功能型高分子生物载体(PET-AQS)能加速生物反硝化,且速率常数Kx与载体投加浓度呈零级反应动力学.在投加PET-AQS 0.056 2 mmol的反硝化体系中,循环使用10次,反硝化速率均是空白体系的1.2倍以上,表明PET-AQS具有良好的重复利用稳定性,有利于实际应用.     

壳聚糖吸附印染废水中结晶紫效果的研究

研究了壳聚糖对染料结晶紫的吸附条件,探讨了壳聚糖添加量、结晶紫溶液初始浓度、温度等因素对壳聚糖吸附性能的影响。结果表明,随着壳聚糖添加量的增加,其对结晶紫的吸附能力也增强;吸附量随结晶紫初始质量浓度的增加而增大,溶液中结晶紫的去除率随其初始浓度的增加也呈缓慢增加趋势;随着吸附温度从30℃升高到50℃,壳聚糖对结晶紫溶液的平衡吸附量有所减少。壳聚糖对结晶紫的吸附动力学符合Lagergren方程二级吸附模型和Elovich方程,吸附过程的表观活化能（Ea）为7．24kJ／mol。     

绿色塑料的发展现状及趋势

文章论述了绿色高分子材料的发展和生态环境协调型生物可降解绿色塑料的产业发展现状及趋势。     

高分子重金属螯合剂合成条件的响应面优化

以实验室制备的大分子多烯多胺为原料,在碱性条件下,制备新型高分子重金属螯合剂二硫代氨基甲酸盐(DTC)。在单因素实验中,研究了反应时间、反应温度、NaOH∶PEI和CS2∶PEI等4种因素对Cd~(~(2+))去除率的影响,随后采用了响应曲面法中常用的中心复合设计模型以Cd~(2+)去除率为响应值建立二次回归方程对DTC的合成条件进行了分析与优化。得到的最佳合成条件为:反应时间10.4 h,反应温度70℃,NaOH∶PEI为1.78,CS_2∶PEI为0.8。此条件下制备的DTC去除Cd~(2+)的效率为99.9%,与模型预测值(100%)相对偏差仅为-0.1%,模型与实际拟合良好,并利用红外傅立叶与扫描电镜对螯合剂进行了理化性质的分析。     

不同温度条件下高分子固化剂改良砂土的强度特性∗

近年来城市热岛效应越加明显,温度变化对土体性质的影响程度备受关注。通过一系列无侧限抗压强度试验,对高分子固化剂改良砂土在不同温度条件下的抗压强度特性进行了研究,并结合微观扫描电镜对改良砂土的微观结构和改良机理进行了研究。结果表明：在相同温度条件下,高分子固化剂改良砂土的强度和弹性模量随高分子固化剂含量的增加而增大;随着温度的升高,高分子固化剂改良砂土的强度和弹性模量一直保持增强趋势,且当温度达到 35℃后,加入 3% 和 4% 含量的高分子固化剂改良砂土的强度增幅变缓;高分子固化剂溶液均匀分散在砂土中,随着水分挥发,在砂粒之间形成了空间网状固化膜,使得分散的土体连接成为一体,从而提高砂土强度;且随着温度的增加,形成的固化膜强度增强,使得改良砂土强度进一步增加。高分子固化剂在高温条件下对砂土依然具有较好的加固效果,可为高温地区防风固沙加固提供新途径。